Reduced outflows to begin as construction resumes as Tuttle Creek Lake stilling basin

The U.S. Army Corps of Engineers at Tuttle Creek Lake has resumed construction associated with the Stilling Basin Rehabilitation project downstream of the dam on what’s commonly known as the tubes.

The first stages will affect the lake level in the short term, in addition to areas around the stilling basin and river pond area. Operations Project Manager Brian McNulty says the initial repair is the replacement of the last concrete wall in the stilling basin.

“We had replaced all of those up to the point that the contract was suspended and this will complete the last one. The damage in the section was the deepest and so it’s the most difficult to repair,” McNulty said.

To facilitate repair work, water will be drawn down in the stilling basin by opening the water control gate at Rocky Ford Dam. Outflow from Tuttle Creek is also being reduced during repair work, with inflow into the lake expected to remain above the minimum planned outflow. The Corps says the lake will be lowered in elevation to 1,071, roughly a foot below normal winter level to provide additional storage space.

McNulty says construction will continue from there.

“It will be several more months at a minimum. The anchor installation is the most difficult part of the project. When I say anchor, these are anchors that are drilled 50 to 60 feet below the basin,” he said.

The anchors are vertical down through the walls and anchor into the bedrock underneath the stilling basin.

“The back wall drain that has caused the sinkholes a couple of times in the history of the lake, that pipe is not in very good shape and these anchors are one of the mechanisms that are being put in place to replace that. That pipe is going to be decommissioned and grouted shut so it’s no longer functional once the job’s done,” he said.

The project was disrupted during the 2019 flooding events at Tuttle Creek Lake. The portion of the river channel, including pedestrian access along the river bank downstream of the stilling basin are clearly marked and continue to be closed. This includes the picnic shelters and east side of the river in Outlet Park will continue to be closed.

No public access, by boat, foot or otherwise is allowed in the construction area of the dam.